1. Field of the Invention
The present invention relates to a method of overwriting data sessions selectively in a multi-session disk.
2. Description of the Related Art
In these days, a rewritable disk such as CD-R and CD-RW as well as a read-only disk such as CD (Compact Disk) is widely used as a storage means of digital data.
Data written in a CD-R or a CD-RW is grouped by a logical track unit (abbreviated ‘track’ hereinafter) which is a data section recorded at a time, and a CD-R or a CD-RW has at least one session which includes at least one track where a session is defined by a user. A CD-R or CD-RW including a plurality of sessions is called ‘multi-session’ disk.
Each session of a multi-session disk is defined at each ‘session close’ request from a user, and therefore the size of each session may be different from each other. For such a multi-session disk, new data should be written as a new session next to the last closed session or as a new track of an unclosed last session.
Therefore, it is not possible to overwrite a useless session including unnecessary data if it is located between neighboring sessions. This restriction reduces disk storage efficiency. To use the space of useless sessions, disk should be erased entirely or area from the first useless session to the last session should be deleted first before recording new data. However, this method is impossible to conduct when a session including valid data exists between the first useless session and the last session.